A crotch muppet is a strange animal that can occur when you don't wash your crotch enough...The animal will look a lot like the muppets and will have a strange voice- they are very hard to get rid of...

Harry: He dude, ur Crotch Muppet s go away yet?
Bob: Nope, they just keep multiplying!
Harry: Hmmm; maybe you should try calling the exterminators. They could get on your girlfriend and try to get in her pants!
Bob: Wow yeah i should. Dayumm that would suck..